GHK Cu Copper Peptide Neck & Face Serum Defy GHK Cu (glycyl L histidyl L lysine) is a naturally occurring copper binding peptide found in human plasma. As levels decline with age, so may its support of the biological processes involved in collagen production, skin BPC 157 + TB 500 Nasal Spray Polar Peptides 2% GHK CU Copper Peptide Serum for Hair Growth and Scalp Care Seraphime Peptide Calculator Cellgenic